First you cut out some different sized circles. Use a synthetic fabric. For best results use organza or I really like nylon lining (the stuff you would put under a satin dress or skirt.) Some synthetics just give you a burnt look and don't curl, so test out your fabric first to see if it will work. Also, your circles don't have to be perfect. I even used some ovals and uneven curvy edges.
Next you take your fabric and brush it ABOVE the flame. The heat will burn it. Don't get it too close or your fabric will catch on fire. Be careful when touching the fabric edge, it's hot!
Soon you'll have a pile of petals! Pile them together smallest to largest and sew a cross in the center to give them a pucker. I found some vintage buttons or beads for the centers. I also glued alligator clips so I can snatch them up and put them on my shirts or in my own hair!